1. Field of the Invention
This invention relates generally to systems and method for reading data from and writing data to data storage medium by employing the data recording technology. More particularly, this invention is related to an improved data access system. The data access system is implemented in a portable data-card drive device that has a high-speed data access subsystem with novel pulse shaping circuit for performing transformer-coupled read/write operations. The transformer-coupled pickup head becomes a removal and conveniently replaceable unit to enhance a long-term reliable and economical operation of the data card drive system.
2. Description of the Prior Art
Conventional technology of reading-writing data on concentric circular data tracks of a flat data storage medium often presents a problem that the data-bit density varies between the outer tracks and the inner tracks. The variable bit density in data storage is due to a geometrical factor that the outer data tracks are much longer in length than the inner tracks. A common practice is to form the inner tracks with a capacity to store the data bit at a higher bit density than that of the outer tracks. Due to the variations of data storage density between the inner and outer data tracks, a more complicated servo control system implemented with more complex signal-processing algorithms is required. Additionally, by varying the data storage density from the inner tracks toward the outside tracks, the data transfer rate is also changed in accessing data from the inner tracks compared to the outside data tracks. More complicated data processing schemes must be applied to deal with such access rate variations. Higher error rates may incur due to these variations between the inner tracks and the outer tracks.
Additionally, a conventional disk drive system implements a directly coupled configuration with the pickup head directly connected to a preamplifier. The directly coupled pickup configuration often imposes a limit on the life span and usefulness of the storage medium as the pickup head is more prone to damages. When a pickup head is damaged, the disk drive system crashes and the whole system becomes useless. Unless properly backed up, the data stored in storage medium with a damaged pickup head would be very difficult to retrieve. For a direct coupled pickup head, this inherent limitation cannot be overcome with the technology currently available in the data recording and storage industry.
Therefore, a need still exists for an improved data-card drive system to overcome the aforementioned difficulties encountered in the prior art. Specifically, this storage card drive system must provide a uniform density for data storage and a data-card drive system to access the data-storage card. Furthermore, it would be desirable that this system is portable and is also provided with several standardized sizes for processing standardized data-storage cards.
Therefore, an object of the present invention is to provide a data storage-card drive system with a pickup head moving above the data-storage card in rotational movement. The data read-write functions are enabled only for arc-segments of the rotational movement such that the data tracks are arranged as plurality of parallel arcs, e.g., half-circles. The pickup head is further configured with a transformer-coupled removable head that can be conveniently replaced such that the aforementioned difficulties and limitations encountered in the prior art can be resolved.
Specifically, it is an object of the present invention to provide an improved transformer coupled pickup head configured as a removal module that can be conveniently removed and replaced. The pickup head is connected to a secondary winding of the transformer with the primary winding connected to a driver for generating write current pulses. The secondary side of the transformer has a greater pulse decay constant to assure that the write current has a sufficient pulse width to overwrite the entire length of the data bits on a data track
Another object of the present invention is to provide an improved transformer coupled pickup head configured as a removal module that can be conveniently removed and replaced. The pickup head is formed as either a magnetic or optical pickup head. For an optical pickup head, the drive system is further provided with an optical to electrical converter to convert optical signals to corresponding electrical signals for transfer through the transformer to a data signal processor.
Another object of the present invention is to provide a data-storage card drive system with a pickup head driven by a motor, e.g., a brushless motor, to rotate over the data-storage card with the rotation axis perpendicular to the card surface. The motor is mounted on a carriage for making horizontal movement along a longitudinal direction of the data card. The position of the pickup head is then servo-controlled by moving the carriage and the motor while the data storage card either stays at a fixed position or the pickup head is rotated and the card makes horizontal linear movements.
Briefly, in a preferred embodiment, the present invention discloses a data storage drive system. The system includes a pickup head for performing data access functions connected to a secondary winding of a transformer. The transformer further includes a primary winding connected to a driver controller provided with a pre-amplifier for generating a data writing pulse. The secondary winding further having a pulse decay-constant adjustment capacitor and a pulse decay-constant adjustment inductor for adjusting a pulse decay constant for generating less than ten-percent sag for the data writing pulse whereby the writing pulse can overwrite an entire bit-length onto a data track In a preferred embodiment, the pickup head and the secondary winding are configured as a removable and replaceable module. In a preferred embodiment, the pickup head is provided with signal reading and writing head for a magnetic or optical flat data-storage medium. In another preferred embodiment, the pickup head is provided with signal reading and writing head for an optical flat data-storage medium. In another preferred embodiment, the drive system is further provided with an optical to electrical signal converter for converting optical signals retrieved from the optical flat data-storage medium to electrical signals.
These and other objects and advantages of the present invention will no doubt become obvious to those of ordinary skill in the art after having read the following detailed description of the preferred embodiment which is illustrated in the various drawing figures.